package edu.lingnan.constroller;

import edu.lingnan.common.Result;
import lombok.Getter;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.multipart.MultipartFile;

import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletResponse;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.UUID;

/**
 * @author xBaozi
 * @description 文件上传和下载
 * @date 22:10 2022/5/3
 **/
@RestController
@RequestMapping("/common")
@Slf4j
public class CommonController {

    @Value("${farm.path}")
    private String basePath;

    @Getter
    private final List<String> legalSuffixList = new ArrayList<String>(){{
        add("jpg");
        add("jpeg");
        add("png");
    }};

    /**
     * @param file 需要上传的文件
     * @description 文件上传
     * @author xBaozi
     * @date 22:10 2022/5/28
     **/
    @PostMapping("/upload")
    public Result upload(MultipartFile file) {
        // file是一个临时文件，需要转存到指定位置，否则本次请求完成后临时文件会删除
        log.info(file.toString());

        // 原始文件名
        String originalFilename = file.getOriginalFilename();
        String suffix = originalFilename != null ? originalFilename.substring(originalFilename.lastIndexOf(".")) : "";
        suffix = suffix.toLowerCase();
        if (!legalSuffixList.contains(suffix)) {
            return Result.error(Result.ERROR_CODE, "请选择正确的文件，仅支持jpg,jpeg,png文件");
        }
        // 使用UUID重新生成文件名，防止文件名称重复造成文件覆盖
        String fileName = UUID.randomUUID().toString() + suffix;

        //创建一个目录对象
        File dir = new File(basePath);
        //判断当前目录是否存在
        if (!dir.exists()) {
            //目录不存在，需要创建
            dir.mkdirs();
        }

        try {
            //将临时文件转存到指定位置
            file.transferTo(new File(basePath + fileName));
        } catch (IOException e) {
            e.printStackTrace();
        }
        return Result.success(fileName);
    }

    /**
     * @param name     文件名
     * @param response 响应对象
     * @description 文件下载
     * @author xBaozi
     * @date 22:15 2022/5/28
     **/
    @GetMapping("/download")
    public void download(String name, HttpServletResponse response) {
        FileInputStream fileInputStream = null;
        ServletOutputStream outputStream = null;
        try {
            // 输入流，通过输入流读取文件内容
            fileInputStream = new FileInputStream(new File(basePath + name));

            // 输出流，通过输出流将文件写回浏览器
            outputStream = response.getOutputStream();

            response.setContentType("image/jpeg");

            int len = 0;
            byte[] bytes = new byte[1024];
            while ((len = fileInputStream.read(bytes)) != -1) {
                outputStream.write(bytes, 0, len);
                outputStream.flush();
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            // 关闭资源
            if (outputStream != null) {
                try {
                    outputStream.close();
                } catch(IOException e){
                    e.printStackTrace();
                }
            }
            if (fileInputStream != null) {
                try {
                    fileInputStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }

    }
}
